It is estimated that there are 10 million people worldwide who are blind due to corneal diseases (See e.g. Carlsson et al. (2003) in a paper entitled “Bioengineered corneas: how close are we?” and published in “Curr. Opin. Ophthalmol. 14(4):192-197”). Most of these will remain blind due to limitations of human corneal transplantation. The major barriers for treating these patients are corneal tissue availability and resources, particularly for people in developing countries. To have corneas available for transplantation, a system of harvesting and preserving them must be in place. This requires locating potential donors, harvesting the tissue within several hours of death, preserving the tissue, and shipping it to the appropriate facility within one week. Patients who have had refractive surgery may not be used as donors. Therefore, a shortage of corneas may occur in the future, even in developed countries, as the number of patients undergoing refractive surgery increases. Even among patients who are fortunate enough to receive a corneal transplant, a significant number will develop complications that will result in the loss of vision. The most common complications are graft rejection and failure and irregular or severe astigmatism. In successful cases, the improvement in vision may take many months following the surgery due to graft edema and astigmatism.
A biocompatible artificial cornea with tissue integration and epithelialization can replace the need for a human cornea and provide excellent surgical outcomes. Such an artificial cornea can eliminate the risk of corneal graft rejection and failure, as well as astigmatism, and enable rapid visual recovery. An artificial cornea will ensure an unlimited supply for transplantation anywhere in the world, without the resources required of an eye tissue bank, and eliminate the concern for human cornea shortages due to refractive surgery. Moreover, the technology developed for the artificial cornea can also be applied to the treatment of refractive errors, such as nearsightedness. Through a procedure known as epikeratoplasty (or corneal onlay), a thin polymer can be attached to the cornea to change the refractive index. A biocompatible epithelialized onlay placed over the cornea has an advantage over current technology of laser in situ keratomileusis (LASIK), which requires irreversible corneal tissue removal.
It would be desired to develop an artificial cornea that supports a stable epithelialized surface. Multilayered, stratified epithelial cells would serve as a protective barrier against infections and prevent destructive enzymes from gaining access to the device-cornea interface. The critical requirements for epithelial support of the device are a biocompatible surface for epithelial cellular adhesion and good permeability of glucose and nutrients through the device to support the adherent cells. Other important characteristics of an artificial cornea include optical clarity, biocompatibility, good mechanical strength, and the ability to integrate with stromal tissue.
Accordingly, it would be considered an advance in the art to develop an artificial cornea encompassing these desirable requirements or characteristics.